1. Field of the Invention
This invention relates to a method of making a silicone gel which discolors less on aging.
2. Description of the Prior Art
Silicone gels are known materials and many are known to be platinum catalyzed. One problem which arises in certain applications is discoloration on aging. The properties of the silicone gel are not altered by the discoloration except where aesthetic value is important or optical properties are required.
The use of vinyl containing polysiloxanes having silicon-bonded hydroxyl and epoxy silane for promoting adhesion of platinum cured compositions is known in the art from U.S. patent application Ser. No. 799,877, filed May 23, 1977 by Jay R. Schulz and entitled "Self-adhering Silicone Compositions and Preparation Thereof" now U.S. Pat. No. 4,087,585. The present invention is specific to silicone gels and to the method for making these gels. It has been found that some improvement is observed in using the combination as described by Schulz, but a significant improvement is obtained by mixing the vinyl containing polysiloxane having silicon-bonded hydroxyl and the epoxy silane separately to the vinyl-containing polyorganosiloxane before the remaining ingredients are added to make the silicone gel.